1. Field of the Invention
The present invention relates to a parts assembly system provided in an automatic production line for plastic products and the like.
2. Description of the Related Art
In recent years, in a production line using an automatic machine, not only assembly of parts but also supplement of parts to each assembly station is automated. Typical techniques for the automation of the parts supplement are automatic guided vehicles (AGV), in which self-propelled conveying carts travel in accordance with a predetermined drive program.
However, the method in accordance with the drive program has a disadvantage that the system becomes complicated as the scale of the line and the number of the conveying carts increase. In this regard, a system has been suggested in which a request for the supplement is made from each assembly station, and the request is received to perform the supplement, without using the drive program (refer to Japanese Patent No. 2978028).
FIG. 9 schematically illustrates this system, which includes a production line 101 where main parts to be assembled are conveyed, a plurality of assembly stations 103 including a stocker 102 of subsidiary parts, and a remain information network 104 which notifies remain information of the stocker 102. On receiving the request for the supplement from each of the assembly stations 103, a control device 105 controls a self-propelled conveying cart 106 which supplies subsidiary parts. In a conveying path 107 of the self-propelled conveying cart 106, a parts placing station 108 for placing parts into the self-propelled conveying cart 106 is provided.
In this parts supply system, when supplement of parts is necessary in the stocker 102, the assembly station 103 issues a parts supplement request to the control device 105 through the remain information network 104. The control device 105 allows the self-propelled conveying cart 106 to travel along the conveying path 107 to supplement the parts in order of requests being received. The supplemented parts are placed into the parts placing station 108 and conveyed to each assembly station.
However, in such a parts supply system, the stocker of the parts supply machine provided in the assembly station necessarily faces the conveying path of the subsidiary parts, and the width of the stocker necessary in the assembly station is different depending on the subsidiary parts. For this reason, if the assembly station is narrow, the subsidiary parts cannot directly be conveyed to the stocker, and it is necessary to manually move the parts in part or prepare a separate conveyor. In addition to the production line, it is necessary to provide the space for the travel of the self-propelled conveying cart across the total length of the production line.